“Drag” refers to forces acting opposite to the relative motion of an object moving with respect to a surrounding fluid. In the case of a projectile traveling through the atmosphere, drag is sometimes referred to as air resistance. The range of a projectile discharged into the atmosphere depends in substantial part on drag. The range of a projectile can be increased if drag can be reduced. Moreover, less force is required to launch a projectile a given distance if drag is reduced.
Reducing the drag associated with a projectile provides many advantages. If all other factors remain constant, reducing the drag reduces the amount of accelerant, such as gunpowder, required to propel the projectile a given distance, allowing for a reduction in the size of the cartridge in which the projectile is packaged. Smaller cartridges in turn allow a greater number of cartridges to be carried in the same amount of space, and thus soldiers and law enforcement personnel can carry a greater number of cartridges into an adverse situation than would otherwise be possible. Alternatively, reducing drag while maintaining the same amount of propellant material will increase the range of the projectile. Increasing the range of a projectile may allow the use of a smaller weapon than would otherwise be required to propel the projectile a desired distance. Where the weapon is used by a soldier, increasing the range may allow the threat to be kept at such a distance that lighter body armor may be used.
A corona discharge is a partial breakdown of a dielectric surrounding a point on a high voltage conductor that has a high electrical stress. Studies utilizing supersonic wind tunnels have shown that a corona discharge formed on the leading edge of an object moving with respect to air can reduce the drag of the object.